Windshield wiper mechanism



June 23, 1953 E. E. slvAcl-:K

WINDSHIELD WIPER MECHANlSM 2 Sheets-Sheet 2 Filed Aug. 16, 1947 IN V EN TOR.

5. d. L f j i f 2 J Patented June 23, 1953 WIN DSI-HELD WIPER MECHANISM4 EmilfE.. Sivacek, Ann Arbor, Mich., asvsignorA to King-Seeley Corporation, AnnA Arbor, Mich., a, corporation ofMichigan Application Augustl, 1947, SerialNo.-768,985-

The; present invention relates to windshield wiper'mechanism and particularly relates to controls for such mechanism whereby the vwind-A shield wiper blades may be parked. in a. predetermined location.

One4 ofthe primary objects of the present invention is. to provide an improved means Afor parking of the windshield Wiper bladeswhen theyl a-rey mechanically driven from a rotating part of the. engine.

Another object of theV invention is. to providev animproved operating structure for. connection with a rotating part of the engine for clutchingand declutching a mechanical. drive tothe wind.- shield wiping blades.

Another object of theinvention is to provide an improved system for control of a fluidY actuated clutch.

Another object isto-provide valve means driven inaccorda-nce with a rotating. part of the wiper mechanismA for parking thereof.

Other objects: of. thel invention will become apparent from the. following specification, the drawings relatingA thereto, andfroml the claims hereinafter set forth. In the drawings in which like numerals' are. used4V throughout' to designate like parts in the severaly views:

Figure. 1 is a partially diagrammatic viewfshow- 15` Claims. (Cl. 15T-253') ing a windshield wiping mechanism embodying the invention;

Fig. 2 is an enlarged view in central vertical section showing a portion of the mechanism shown in Fig. 1;

Fig. 3' is a view taken substantially along the line 3 3 of Fig. 2;

Fig. 4 is a view similar to Fig. 1 showing a modified form of the invention; and Y Fig. 5 is a partially schematic view showing a modified form of the yfluidvv actuating means for the clutch mechanism in central vertical cross section.

Although the present invention is specifically illustrated as being associated with windshield wipers and while it has particular lutility when so used, it will be appreciated by those skilled in the art that, in generic aspects, it has other uses within the scope of the present invention in which the drawings are to be taken as being illustrative rather than limitative of the invention which is to be limited only by the scope of the hereinafter appended claims.

Referring t0 the drawings, the numeral I designates generally a pair of wiper blades carried bythe usual arm 2 in the usual pivot 4 adjacent a windshield of a motor vehicle or the like. The arm .2, and associated wiper blade I are rocked backwardly and forwardly over the windshield surface by means yof a pair of links 6 pivotally secured as at. 3. at. one end portion.

thereof. to the arm2 and at the adjacent end portions thereof to. a common. crank arm, I0, carried by. rotating'stubV shaft I 2 journaledwithin ahousing I4.. Energy for oscillating they bladesv I and-crank arm II]l is obtained from asuitf. ablerotating.A Dart, of the. engine, with which. the windshield.l wiping. mechanism .may be associ, ated..and.as by. a shaft. I6. The. shaft I5 is, suitably geared for driving. a Avertically arranged. shaft, Idjournaled within a housing 20J Avvariablespeed friction. typev transmission mechanism generally designated 2.2 comprises a driving .wheel- 2l rotatable. with butmovable longitudinally of the. shaft II8,.and.,awh,eel, 2,3 arranged to be driven. by the wheel 2,I about anaXis extending, radially of, the Whee1,2|. The Wheel 2.3is con.- nectedthrough a clutch. mechanismv 24,.to. a flexible. drive. shaft 25. havingat its .other end al worm` 28, for driving a. Wormwheel. 30. journaled. inl thehousingl 4. Thestub shaft.. I 2 is resiliently urged by springvk 2,'I, towardI the., wheel 3 and carries a pin, 29 .whichis normally received Within a recess. 3l, in the wheel.30.. Thespring 2,'I.,eX,-. erts4 sufcient force. to maintain. thev pin 2,9 in recess..3I during normal operation., of .the .Wiper vblades I, however, in the event the blades I are,

manually moved, the pinA 2,9. willride out. Of the recess.l 3l.; such movement, beingpermitted by. the spring 2.1i.. Uponstarting. of. the. wiper. meehanismvvithv the pin 2.8. out of` theY recess 3l, the Wheel 3l]- will rotate until'the, pin 2'9 is again in, registry with. the single, recess 31 at which time the spring 2 1 urges, it thereinto and thebladesr I may again be drivenbyy the wheel 3Q in prede,- terminedrelation.tothe position of the blades, I

A .f1yba11type governor generally designated 3,2.. is` loca-ted .within the housing 211 and. carried by the` shaft ISQQI'. adjusting the radial position of the driving wheeL 2| on the friction plate or drivenwheel 2,3 ofthe transmission mechanism. 2 2` whereby the flexible shaftZ. may be driven at asubstantially constant speed, irrespective of the speedof. rotation of. the. shafts I 6 and I8. which areY rotated at a, speedlproportional tothe speed 0f thev vehicle engine. The. housing 20 is.

provided with a pair of spaced vertically alignedA 5.5 of the shaftylo anddetermnes the. speedat whichthe wheel 23, will be dri-ven. LAS will be obvious,l anincreasing speedof rotation of the shaft. i8. will cause. the. ily-balls 5.0 to draw the sleevemember downwardv longitudinally ofl the 3 shaft I8 whereby the driving Wheel 2| will be made to engage the driven wheel 23 at a greater distance from the center of rotation thereof and conversely.

The wheel 23 has a journal portion 60 which is held in a bearing carried by the housing 28 extending in a radial direction from the Wheel 2|. Spring 58, located concentric with the journal portion 68, has one end portion abutting the adjacent surface of the friction plate or wheel 23 and its other end engaging an antifriction device 59 carried by the side wall of the housing 28 whereby the spring 58 may rotate with the wheel 23 and its expansive force will act to maintain the wheel 23 tightly against the peripheral surface of the driving wheel 2|. The outwardly extending end of the'portion 68 has a projecting tooth or drive portion 6| for engaging in a similarly shaped slot 6|a in the adjacent terminal member 62 of the flexible shaft 26. The shaft 26 may be clutched to and declutched from the friction plate 23 by longitudinally moving the rotatable member 63 thereof. A spring 64 is arranged concentrically about a reduced diameter shank portion of the member 62 and is of such a length that when the member 62 is in its driving portion with the tooth 6| in the slot Sla, the spring 64 will be unstressed and free to rotate with the member 62 or rest in the end portion of the housing of cable 26 as the case may be.

As shown in Fig. 2, the Worm 28 has oppositely extending journal portions 68 and 61 which are rotatable and longitudinally movable in bearings 10 and 12 respectively provided in the housing I4. The longitudinal position of the worm 28 within the housing |4 and consequently the clutching of themember 62 with the tooth 6| is controlled by a fluid actuator 18. The fluid actuator 18 comprises a pair of fluid chambers 82 and 84 having a flexible diaphragm 88 serving as a common wall; the center of the diaphragm 88 being in substantial axial alignment with the worm 28. The journal portion 61 extends completely through the bearing 12 and has a circumferential groove 88 therein providing a pair of spaced shoulders. A substantially U-shaped member 98 has its open end suitably secured to the diaphragm 88 and has a central aperture through its bottom Wall through which the journal portion 61 extends whereby the bottom Wall is held between the spaced shoulders formed by the circumferential groove 88. 'As the diaphragm 88 exes under a differential in pressure between that in the chamber 82 and that in the chamber 84, the worm 28 will be moved longitudinally to the right or to the left whereby the movable member 63 will be longitudinally moved for clutching and unclutching the member 62 with the tooth 6I. The position of the diaphragm 88 with the member 62 clutched to the tooth 6| is substantially planar as shown and the length of the parallelly extending arms of the member 98 is preferably chosen with respect to the position of the diaphragm under the differential in pressure between the chambers 82 and 84 normally maintained during operation of the windshield wiper mechanism soA that little if any frictional force is exerted by member 98 against the shoulders of the groove 88 during rotation of the shaft 26.

The direction of rotation of the Worm 28 is chosen so that when the Worm 28 is driving the Wheel 38, the reaction force will tend to maintain a circumferential shoulder 14 of the worm 28 against the adjacent end Wall of the bafn worm wheell 38 the ports |48 and |42 will be in- 18 in which position the rotatable member 63 is in. its longitudinally moved position to provide clutching of the member 62 with the tooth 8|. Upon operation of the actuator 18 in the opposite direction, the Worm 28 and rotatable member 63 will be longitudinally moved against the force of the spring 64 to unclutch the member 62 from the tooth 6| in which position a spring pressed ball detent 16 will move into a circumferential recess 11 of the journal portion 86. The holding force of the detent 16 is sufficient to hold the member 63 against movement under the force of the spring 64 with no pressure differential between the chambers 82 and 84 but is insuicient to Vhold the member 63 against movement to clutching position of the member 82 with tooth: 8| when the pressure in chamber 82 is lower than that in chamber 84.

Any suitable source of differential in iiuid pressure may be utilized 'to actuate the diaphragm 86. However, since the windshield wiper mechanism herein described is particularly adapted for use on a motor vehicle the low pressure in the intake manifold of the conventional engine with which most motor vehicles are operated may be used to provide the reduced pressure and the atmospheric pressure may be used to provide the higher pressure for actuation of the diaphragm 88. As shown the intake manifold of the engine or any other sub-atmospheric pressure is conducted through a conduit |88 having one end connected to the intake manifold of the motor vehicle engine and its other end connected to a port |81 of a three-way valve |88 diagrammatically shown as comprising a base portion H8 having ports |81, H2, H4 and H8 opening through an upper surface H8. A movable plate |28 is adapted to be moved as by the knob |2| whereby the port |81 may be selectively connected with either of the ports H2, H4. right-hand or parked position, the port H2 is connected to atmosphere through a port |22 in the plate |20 and the port |81 is connected with port H4; the port H6 being closed. The port H6 is connected to atmosphere through a port |24 and the port H2 is connected to the port |81 with the port H4 closed when the valve |88 is in running position. The port H2 is connected by a conduit |28 directly to the pressure chamber 82 of the fluid actuator 18. The port I4 is connected by a conduit |28 to a rotary valve |38. Conduit |32 connects the valve |38 'With the fluid pressure chamber 84. A conduit |34 connects the port H8 with the conduit |32 intermediate the valve |38 and the chamber 84.

The valve |38 comprises a rotatable disk |38 havinga passageway |38 which periodically connects ports |48 and |42 to establish fluid flow communication therebetween. The conduit |28 is connected to the port |48 While the conduit |32 is connected to the port |42. It will therefore -be obvious that once during each revolution of the terconnected vfor fluid flow by means of the passageway |38 and fluid iiow through the conduits |32 and |28 will be prevented during the other remaining portion of the rotatable member |36. By properly positioning the rotatable member on the worm wheel 38 the conduits |28 and |32 may be opened for fluid ow therebetween and at such a position of the stroke ofthe Wiper blades I that the diaphragm 86 will be operated to declutch the member 82 from the tooth 6| so that windshield Wiper blades will come to rest in a desired predetermined parked position.

It is believed that the remaining details of con- With the valve in the extremev struction may best be described by reference to the operation of the windshield wiper system is communicated from the conduit |66v through the ports |01 and ||2.an`d`the conduit |26 to the pressure chamber 82. Atmospheric pressure is communicated to the chamber 84 through the ports I|6, |24 and conduits |34` and |32 whereby the diaphragm 86 holds the worm 28 in a righthandV position, as viewed in Fig. 2, in which the recess 'I'I is out of holding relation with the spring detent I6 and the member 62 clutchedto'thetooth 6|. The engine-accessory to` which the shaft I6 is'connected will drive the shaft Iwhich ,in turn drives the wheels 2| and 23 forl driving the 'rotatable member 63. member-63 .rotates the worm 28 driving thewheel for rotating the stub shaft I2 and consequently the windshield wiper blades I. If during the time thatthe valveY I 08 was in parked position, the wipers I had been. manually moved away from their parked position, the windshield Wipers will not commence to rotate until such time that the pin 29 and` slot; 31 comel into registry. As such time, the spring 26y forces the pin 29=into the slot 3| and the wiper will be driven by the engine as long as the valve |08 isin the .run position.

Because in the usual operation of a motor vehicle the speed of the engine varies considerably, the flyball governor 32 is provided byV which the driving wheel 2| is moved up and down vertically on the shaft I8. The circumferential surface of wheel 2| will engage the driven wheel 23 at Various radial distances so that the rotational speed of the wheel 23 relative to that of the wheel 2| will be varied. The governor 32v is so arranged that as the speed of the shaft I8 increases the wheel 2| will be drawn downwardly engaging the driven wheel 23 at a greater radius whereby the more rapid rotation of the member 2| will act to drive the driven wheel 23 at substantially the samespeed. Conversely if the speed of the motor decreases,.the centrifugal force exertedby the iiyball 58 will be less and the spring 54Y will be permitted to more the driving wheel 2| upwardly to drive the driven wheel 23 at a lesser radius whereby the slower rotational speed of the driven wheel 2| will drive the driven wheel 23 at substantially the samespeed as before.

When it is desired to park the blades I, the valve |08 is moved to the parked position or to the right from that shown. Sub-'atmospheric pressure will then be communicated from vthe port |07 to the port I|4 and through the conduit |28 to the valve |30. Atmospheric pressure is now admitted through .the ports |22 and I l2 through conduit |26 to the pressure chamber 82 without effect. When the rotatable member |36 presents its passageway |38 so that it interconnects the ports |40 and |42 this sub-atmospheric pressure will betransmittedthrough the conduit |32 to the pressure chamber 84. When the valve |30 opens the source of sub-atmospheric pressure to the chamber 84, the diaphragm 86 is flexed to the left as seen in Fig. 2 thereby moving the worm wheel 28 bodily to the left and moving the rotatable member 63 so that the member 62 is de- Rotation of the-rotatable;

61. clutched from the rotating` tooth 6|-. Rotation of the rotatable member 63 will stop almost immediatelyV due to the relatively small amount of inertia in the moving parts. Movement of the worm 28 Vwill also cause a slight advance in rotation of the worinY wheel 30 whereby the-windshield wiperv blades I are moved into parked position.

In Figs. 4 and 5, somewhat modified forms of the invention are provided.' In Fig. 4, the fiuid motor 'I8' which corresponds in general to the fluid motor 'I8 is providedv on the shaft I8 and forms part of the housing 20." bolted to the engine accessory as shown rather than as shown in Fig. 2 adjacent the worm 28and forming part of the housing I4. The shaft I8' in Fig. 4 contains a single tooth 6| which is engageable with a rotatable member `62 of the engine accessory so that the shaft I8 is directly clutched thereto and declutched therefrom. A spring |43 is arranged concentrically with the shaft I8 and acts to urge the member 62 into clutching engagement with the vtooth 6|. One endr of the spring |43 abuts a ange |44 of the shaft I8 and the other end engages a washer |46 loosely received on the shaft I8 and engageable with a shoulder |48' of the housing 20. With the tooth 6|.' clutched'to the member 621; the spring |43 exerts no force and consequently is free to remain stationary or to rotate with the shaft |8 similarly to the spring 64 and member 62. In thisv form, itis unnecessary for the movable member l63 of the flexible shafting to move longitudinally and therefore the spring 64 may be omitted and neither will member .63 be required to rotate except when thewiper mechanism is being operated to reciprocate the blades I. In this form aY journal portion l-similar to the journal portion 61 is operatively connected to the diaphragm 86 and is slidably heldvfor reciprocal movement in a bearing |52. A circumferentialrecess |54 cooperates withaspring pressedv ball detent |56 in a manner similar to the recess 'I'I anddetent vItl and acts to hold the shaft I8- in a position in which the tooth 6| is declutched from the member 62.. In other respects the modification shown in Fig. 4 is similar to the form shown in Figs. 1,2, and .3 inclusive and acts to drive and park the windshield wiper blade I in avmanner similar to that described with respectto the first-mentioned form upon operation of `the control Vvalve |88. Itis therefore, deemed unnecessaryV to` complicateV this specification byr providing a detailed explanation of the operation thereof.

In Fig..5r there is shown a modified form. of detent mechanism in which the journal portion |50` is provided with a straight walled slot or circumferential recess. I 54 with which a pressure-actuated catch |58 is cooperable. The housing.20- isprovidedwith a piston chamber |60 in which is reciprocallypositioned a piston |62 carryin'gthecatch |58. The pistonA |52 is normally urged'in an inward `direction towardfthe journal portion |50 by spring |64. In this modification, the conduit' |26, instead of being connected to the chamber 82, is connected to the piston chamber of rthe housing 20 above the piston |62, so that when the valve |08 is rotated to run position, subatmospheric pressure will. be'v ,transmittedfromthe valve port I2 to the space above thepiston |62 wherebythepiston |62 will be moved outwardly,.releasing the catch |5B'jfro`m the circumferential grooveror'recess |.541'permittingthe springjllwto` move the shaft I8 to the leftyas seen in Fig. 4; whereby theV tooth"6`|fis clutched with the member 62. Since during running operation sub-atmospheric pressure will always be maintained in the port H2 and consequently in the chamber space above the piston |82, the catch |58 will be held outwardly from the journal portion |50 and will not impede to rotational movement of the shaft I8'. In all other respects the operation of the modification of the form shown in Fig. is the same as that of the form shown in Fig. 4 and a detailed explanation is deemed unnecessary.

What is claimed and is desired to be secured by United States Letters Patent is as follows:

l. In a mechanism of the character described, a rotating part adapted to be driven by a source of power, a reciprocal member driven by said part and adapted to drive a reciprocatingr element, a clutch mechanism adapted Ito declutch said part from said source, a fluid pressure actuator for controlling the declutching of said mechanism, valve means controlling said actuator and actuatable by said part at a desired reciprocal position of said member, and means rendering said valve means inoperable to actuate said actuator at all other reciprocal positions of said member whereby the element may be parked at a desired position.

2. In a Windshield wiping mechanism, a rotating part adapted to be driven by a source of power at substantially constant speed, a reciprocal member driven by said part and adapted to drive a wiper, a clutch mechanism adapted to declutch said part from said source, a fluid pressure actuator for controlling the declutching of said mechanism, and valve means controlling said actuator land actuatable by saidpart at a desired reciprocal position of said member, and means rendering said valve means inoperable to actuate said actuator at all other reciprocal positions' of said member whereby the wiper may be parked at a desired position.

3. In a windshield wiping mechanism, a rotating part adapted Vto be driven by a source of power, a reciprocal member driven by said part and adapted to drive a wiper, a clutch mechanism adapted to declutch said part from said source, a fluid pressure actuator for controlling the declutching of said mechanism, and rotatable valve means controlling said actuator and having a part thereof rotatable with said rst named part, said valve means being operable to actuate said actuator in a single rotary position of saidl part whereby the wiper may be parked at a desired position.

4. In a windshield wiping mechanism, a rotating part adapted to be driven by a source of power at substantially constant speed, a reciprocal member driven by said part and adapted to drive a wiper, a clutch mechanism adapted to declutch said part from said source, a fluid pressure actuator for controlling the declutching of said mechanism, valve means controlling said actuator and actuatable by said part at a single desired reciprocal position of said member whereby the wiper may be parked at a desired position, and manually operable means for selectively rendering said valve means ineffective.

5. In a windshield wiping mechanism for an automotive vehicle, means adapted to be driven by a rotating part of the vehicle engine and including an output element, a rotating drive member operatively connected to said element, a reciprocating member operable to drive a wiper, means coupling said drive member to said reciprocating member and including a rotating portion the rotative position of which is proportional to the reciprocative position of said reciprocating member, conduit means adapted to be connected to a fluid pressure differential maintaining means, a clutch mechanism for connecting and disconnecting said drive member to and from said element, a fluid pressure actuator for controlling said clutching mechanism, and valve means controlled by said rotating portion and operable at a single position of said rotating portion to control the uid pressure at said actuator whereby said clutch mechanism is operable to disconnect said drive member so that the wiper will be parked in a given position.

6. In a windshield wiping mechanism for anv automotive vehicle, means adapted to be driven by a rotating part of the vehicle engine and including an output element, a rotating drive member operatively connected to said element, a reciprocating member operable to drive a wiper, means coupling said drive member to said reciprocating member and including a rotating portion the rotative position of which is proportional to the reciprocative position of said reciprocating member, conduit means adapted to be connected Y to a fluid pressure differential maintaining means,

a clutch mechanism for connecting and disconnecting said first-named means to and from the engine rotating part, a uid pressure actuator for controlling said clutching mechanism, and valve means controlled by said rotating portion and'operable at a single position of said rotating portion :to control the iiuid pressure at said actuator whereby said clutch mechanism is operable to disconnect said drive member so that the wiper will be parked in a given position,

7. In a windshield wiping mechanism for an automotive vehicle, means adapted to be driven by a rotating part of the vehicle engine, said means including a driven element, a rotating drive member driven by said means, a crank arm driven by said member, a reciprocating member connected to said arm, conduit means adapted to be connected to a fluid pressure dierential maintaining means, a clutch mechanism for clutching said rotating member to the engine part, a fluid pressure actuator for said clutching mechanism and operable at a predetermined pressure diifer- Cntial to declutch said rotating member from the engine part, and rotating valve means rotatable in synchronism with said arm'and operable at a single rotative position thereof to provide said predetermined pressure to said actuator whereby the rotation of said rotating member will be arrested at a given position.

8. In an apparatus of the character described, a longitudinally movable rotatable shaft adapted to be rotated by a source of power, a friction wheel, a rotating drive member driven by said wheel and adapted to drive a wiper blade, a rotatable drive wheel carried by said shaft and engaging said friction wheel for rotating said friction wheel, said friction wheel being rotatable by and longitudinally movable relative to said shaft, governor mean'sresponsive to the speed of rotation of said shaft and operatively connected to control the longitudinal position of said friction wheel relative to said shaft whereby said friction wheel is rotated at substantially constant speed irrespective of the speed of rotation of said shaft, clutch means operable to clutch said shaft to and declutch said shaft from the power source, and means responsive to the rotative position of said drive member for declutching said shaft at a predetermined rotative position of said disk.

9. In a windshield wiping mechanism adapted to be connected to a source of rotative pcwer,`

means for reciprocably moving a wiper blade, a housing member, a rotative Velement operatively connected to said means and having a portion carried within said housing and movable with respect thereto, a pair of cooperable clutching elements, one of said pair of elements being adapted to be continually rotated by-the source, the other of said pair of elements being carried by said rotative element, means urging said pair of elements into clutching position for drive of said rotative element by the source, a iluid pressure actuator operable upon actuation to move said rotative element portion relative to said housing whereby said pair of elements are separated, and control means for said actuator rotated in timed relation with said reciprocably moving means and operable at a single position thereof toactuate said actuator whereby the blade is parked in a desired position.

10. In a windshield wiping mechanism adapted to be connected to a source of rotative power, means for reciprocably moving a wiper blade, a housing member, a rotative element operatively connected to said means and having a portion carried within said housing and movable with respect thereto, a pair of cooperable clutching elements, one of said pair of elements being adapted to be continually rotated by the source, the other of said pair of elements being carried by said rotative element, means urging said pair of elements into clutching position for drive of said rotative element by the source, a fluid pressure actuator operable upon actuation to move said rotative element portion relative to said housing whereby said pair of elements are separated, control means for said actuator rotated in timed relation with said reciprocably moving means and operable at a single position thereof to actuate said'actuator whereby the blade is parked in a desired position, and means for holding said rotative element in its moved position.

11. In a windshield wiping mechanism adapted to be connected to a source of rotative power, means for reciprocably moving a wiper blade, a housing member, a rotative element operatively connected to said means and having a portion carried within said housing and movable with respect thereto, a pair of cooperable clutching elements, one of said pair of elements being adapted to lbe continually rotated by the source, the other of said pair of elements being carried by said rotative element, means urging said pair of elements into clutching position for drive of saidl rotative element by the source, a uid pressure actuator operable upon actuation to move said rotative element portion relative to said housing whereby said pair of elements are separated, control means for said actuator rotated in timed relation with said reciprocably moving means and operable at a single position thereof to actuate said actuator whereby the blade is parked in a desired position, and spring actuated detent means for holding said rotative element in its moved position.

12. In a windshield wiping mechanism adapted to be connected to a source of rotative power, means for reciprocably moving a wiper blade, a housing member, a rotative element operatively connected to said means having a portion carried within said housing and movable with respect thereto, a pair of cooperable clutching elements, one of said ypair of elements being adapted to be continually rotated by the source,

the other of said pair of elements being carried by said rotative element, means urging said pair of elements into clutching position for drive of said rotative element by the source, a iiuid pressure actuator operable upon yactuation to move said rotative element portion relative to said housing whereby said pair of elements are separated, control means for'said actuator rotated in timed relation with said reciprocably moving means and operable at a single position thereof to actuate said actuator whereby the blade is parked in a desired position, and fluid pressure means for locking said rotative element in its moved position.

13. In a windshield wiper mechanism, a iiexible tubular housing, a iiexible drive member located within said housing and being rotatable and longitudinally movable with respect thereto, means adapted to drive said member from a rotating member and including a clutch mechanism operable to be rendered ineffective to drive said member upon longitudinal movement thereof, a fluid pressure actuator having a movable wall, means operatively connecting said wall to said drive member whereby the position vof said wall is operable to determine the longitudinal position of said drive member, means operatively connected to said drive member for rotation thereby and adapted to reciprocate a windshield wiper blade, fluid pressure control means for said actuator, and means controlled in accordance with the reciprocative position of the blade for actuation of said control means whereby said clutch mechanism is rendered ineffective Ato drive said member.

14. In a windshield wiper mechanism, a ilexible tubular housing, a flexible drive member located within said housing and being rotatable and longitudinally movable with respect thereto, means adapted to drive said member from a rotating member and including a clutch mechanism operable to be rendered ineffective to drive said member upon longitudinal movement thereof, a fluid pressure actuator having a movablel wall, means operatively connecting said Wall to said drive member whereby the position of said wall is operable to determine vthe longitudinal positionV of said drive member, means operatively connected to said drive member for rotation thereby and adapted to reciprocate a windshield ywiper blade, fluid pressure control means for said actuator, means controlled in accordance with the reciprocative position of the blade for actuation of said control means whereby said clutch mechanism is rendered ineffective to drive said member, and releasable means operable to maintain saidA drive member in its longitudinally moved position.

15. The combination of claim 14 in which said releasable means is a spring pressed detent member.

EMIL E. SIVACEK.

References Cited in the iile of this patent UNITED sTATEs PATENTS Number Name Date 397,716 Hart Feb. 12, 1889 864,547 Lemmon Aug. 27, 1907 2,031,830 I-Iansmann Feb. 25, 1936 2,079,573 Lauer May 4, 1937 2,243,016 Prichard May 20, 1941 2,388,857 Lindsley Nov. 13, 1945 

